Effect of environmental factors on the fruit essential oils of Pistacia terebinthus L. growing wild in Turkey

Background: The aim of this study was to investigate the effect of environmental factors on the essential oil yields (EOYs) and major essential oil components in the ripe fruits of Pistacia terebinthus L. (turpentine tree), which is a medicinal and aromatic plant. Fruit samples were collected from 34 different locations of the turpentine tree growing wild in the Lake District in the Mediterranean Region of Turkey. EOYs (%, v/w) and essential oil component ratios (%) were determined in fruit samples by hydrodistillation and GC-MS methods, respectively. The effect of environmental factors on these variables were analyzed using Pearson Correlation and Principal Component Analysis. Results: The essential oil yield of fruits collected from different localities ranged from 0.05% (v/w) to 0.19% (v/w). In terms of average values, alpha-pinene with 41.01% and limonene with 14.28% were the major components in the essential oils of ripe fruits. Among the environmental variables, longitude and sand % in 10-30 cm were the variables that made a statistically significant difference (p < 0.05) in fruit essential oil yield. According to the results of principal components analysis (PCA), alpha-pinene and Ocimene components were most affected by silt (%, 10-30 cm) and pH (%, 30-50 cm) ratios. The longitude and total annual precipitation (mm) were the most determining variables in the sabinene and limonene components, respectively. It was seen that the total lime ratios at different depth levels of the soils taken from the localities were the most effective variables for Myrcene and p-Cymene components. Conclusion: The study findings showed that EOYs and intended volatile component ratios in ripe fruits of turpentine trees grown under appropriate environmental conditions can be increased.